Compensatory strategies during the side hop test in individuals with chronic ankle instability.

CONTEXT: Individuals with chronic ankle instability (CAI) exhibit altered movement strategies during side-cutting tasks. However, no studies have investigated how the altered movement strategy affects the cutting performance.

OBJECTIVE: To investigate compensatory strategies in the side hop test (SHT) in individuals with CAI, with a focus on the entire lower extremity.

DESIGN: Cross-sectional study.

SETTING: Laboratory.

PATIENTS OR OTHER PARTICIPANTS: A total of 40 male soccer players (CAI, n = 20, age- 20.35 ± 1.15 years, height- 173.95 ± 6.07 cm, weight- 68.09 ± 6.73 kg; Control, n = 20, age- 20.45 ± 1.50 years, height- 172.39 ± 4.39 cm, weight- 67.16 ± 4.87 kg).

INTERVENTION(S): The participants performed three successful SHT trials.

MAIN OUTCOME MEASURES: We calculated the SHT time, torque, and torque power in the ankle, knee, and hip joints during SHT using motion-capture cameras and force plates. When the confidence intervals for each group did not overlap by more than 3 points consecutively in the time series data, it was determined that there was a difference between groups.

RESULTS: Compared to the control groups, the CAI group showed (1) no delayed SHT time; (2) smaller ankle inversion torque (0.11-0.13 Nm•kg-1), and greater hip extension (0.18-0.72 Nm•kg-1) and abduction torque (0.26 Nm•kg-1); (3) smaller concentric power in ankle dorsiflexion/plantar flexion (0.18 W•kg-1) and inversion/eversion (0.40 W•kg-1), greater concentric power in hip flexion/extension (0.73 W•kg-1), and greater eccentric power in knee varus/valgus (0.27 W•kg-1).

CONCLUSIONS: Individuals with CAI are likely to rely on hip joint function to compensate for ankle instability, without any differences in the SHT time. Therefore, it is necessary to consider that the movement strategies of individuals with CAI could differ from those of healthy individuals, even if there is no difference in the SHT time.